The invention relates to a liquid packaging container, especially in oblong form, which is formed by folding a die-cut cardboard blank coated on one or both sides with plastic and/or duplexed to aluminum foil, having a planar, rectangular folded bottom sealed in a liquid-tight manner with an overlapped seam and a protected edge on the inner-lying bottom fold-in panel.
Liquid packaging containers of coated cardboard are made with a folding bottom with overlapped seam or with a folded bottom with a laid-flat joining seam. Folded bottoms with overlapped seam are indeed less expensive both in consumption of material and in the apparatus required for folding and sealing, but on the other hand they have at least one open cut edge in contact with the contents, and this is not acceptable for certain kinds of filling, such as filling with hot liquids, aseptic filling and gas-tight filling.
Overlapped-seam packaging containers are known from DE-AS No. 17 61 255, in which two notches are provided in the bottom tuck-in panel, which define a backfolding area which is folded over with its front edge reaching past the axis of symmetry of the bottom. In this known arrangement, however, the backfolding area in the neighborhood of the bottom seam produces a bulge making the bottom surface uneven and can lead to leaks by the formation of a channel. Also, this arrangement is limited to folded bottoms having tuck-in panels.